Methods of and apparatus for stacking veneer sheets

ABSTRACT

Sheets of veneer held against overhead belts by a pressure differential are moved over a plurality of bins, stripped from the belts over a selected bin, grasped at a leading portion, positively aligned against an abutment and deposited in the selected bin to form a stack.

United States Patent Inventors Lewis M. Yock Tiglrd; Robert A. Browning, Jr, Portland, both of, Oreg.

App]. No. 789,539

Filed Jan. 7, 1969 Patented June 8, 197 1 Assignee The Coe Manufacturing Company Painesville, Ohio METHODS OF AND APPARATUS FOR STACKING VENEER SHEETS 17 Claims, 28 Drawing Figs.

US. Cl 209/74, 271/68, 271/74, 271/88, 271/89, 271/85 Int. Cl 1107c 5/38 Field of Search 209/73, 74, 111.6,111.7;271/64, 68, 86, 87, 88, 82, 79, 69, 74, 85

[56] References Cited UNITED STATES PATENTS 1,465,385 8/1923 White 271/79 1,569,256 1/1926 Bobst 271/79 1,854,775 4/1932 Wichmann. 271/85 2,406,857 9/1946 Saul 271/88 2,573,852 11/1951 Lawrence 271/85X 2,736,431 2/1956 Coleman et al. 209/11l.7 3,038,604 6/1962 Muller 209/82 3,476,241 11/1969 Ungerer 271/64X Primary ExaminerAllen N. Knowles Attorney-Watts, Hofi'mann, Fisher and Heinke ABSTRACT: Sheets of veneer held against overhead belts by a pressure differential are moved over a plurality of bins, stripped from the belts over a selected bin, grasped at a leading portion, positively aligned against an abutment and deposited in the selected bin to form a stack.

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METHODS OF AND APPARATUS FOR STACKING VENEER SHEETS This invention relates to methods and apparatus for handling and stacking sheets of wood veneer.

In the manufacture of wood veneer, the long strips of veneer are clipped into sheets of selected sizes. For convenience in handling and processing the clipped sheets, commonly referred to as veneer sheets or veneers, it is often desirable to arrange the sheets in a stack or in separate stacks according to sheet size and/or veneer grade etc. Because veneer sheets are flexible and fragile it is relatively difficult to automatically handle a continuing supply of sheets quickly and efficicntly and to accurately align the sheets into one or more orderly stacks.

An object of this invention is to overcome the above-mentioned and other difficulties in handling veneer sheets by providing new and improved methods of and apparatus for efficiently and automatically stacking or sorting and stacking veneer sheets to grade and/or length, etc.

Another object of this invention is to provide novel methods of and apparatus for stacking sheets of veneer in one or a plurality of stacks and to stack the sheets at stations, according to the length of each sheet, with at least one edge of each sheet aligned with an edge of the stack.

Another object of the invention is to provide novel methods of and apparatus for handling sheets of veneer in which the sheets are frictionally engaged with moving belts above the sheets by a pressure differential, transported with the belts, stripped from the belts at a predetermined location to form a stack, and a leading portion of each sheet is grasped and positively pulled against an aligning abutment.

Another object of this invention is to provide novel and improved apparatus of of the character referred to including means receiving the leading edge of a sheet of veneer as it is stripped from beneath the conveyor, providing at least partial support for the sheet by a flow of gas therebeneath, yieldably gripping and drawing the leading edge of the sheet against a fixed abutment with a movable clamping means, and automatically moving the clamping means and providing the flow of supporting gas in response to a sheet of predetermined size being at a predetermined location in advance of and moving toward the clamping means.

A further object of this invention is the provision of novel and improved apparatus for aligning veneer sheets that are carried along a predetermined path and transferred to a stack of sheets, including a fixed stop member, a lower alignment member to receive and support a leading edge of the sheet and an upper alignment member initially displaced from and subsequently movable into overlying clamping relationship with I the lower member to clamp a veneer sheet therebetween, and means to move both alignment members concurrently in the direction of sheet movement past the fixed stop member to carry the leading edge of a veneer sheet into abutment with the stop and strip it from the alignment members as the sheet is transferred to a stack.

These and other objects, features and advantages of this invention will become better understood from the following description of a preferred apparatus shown in the accompanying drawings, in which:

FIG. 1 is a plan view of automatic veneer sorting and stacking apparatus embodying the present invention;

FIG. 2 is a side elevational view of the sorting and stacking apparatus of FIG. 1 showing the general overall arrangement of the apparatus;

FIG. 3 is a partial side elevational view of the sorting and stacking apparatus of FIG. 2, on an enlarged scale, showing additional structural details;

FIG. 4 is a plan view of the apparatus of FIG. 3;

FIG. 5 is an end elevational view of the apparatus of FIG. 3, viewed from the left-hand side;

FIG. 6 is a fragmentary detailed view taken approximately along the line'6-6 of FIG. 3;

FIG. 7 is a fragmentary side elevational detailed view, with parts removed, of the apparatus of FIG. 6;

FIG. 8 is a partial end elevational view of the aligning apparatus shown in FIG. 4, on an enlarged scale;

FIG. 9 is a partial side elevational view of the aligning mechanism of FIG. 8 viewed from the right-hand side;

FIGS. 10 to 13 are diagrammatic side elevational views of the aligning mechanism of FIG. 9, illustrating the sequence of operation in receiving and aligning a veneer sheet to form a stack;

FIG. 14 is an enlarged side elevational view, with parts removed of a portion of the aligning mechanism of FIG. 9, illustrating structural details;

FIG. 15 is a plan view of the apparatus shown in FIG, I4, with parts removed;

FIG. 16 is an end elevational view of a movable end aligning abutment and proximity switch;

FIG. 17 is a side elevational view of the apparatus of FIG. 16 as viewed from the left side;

FIG. 18 is a fragmentary side elevational view of apparatus similar to that shown in the preceding figures, showing an alternative construction;

FIG. 19 is a fragmentary end elevational view of the apparatus of FIG. I8;

FIG. 20 is a diagrammatic side elevational view of the sorting and stacking apparatus with parts removed, illustrating the location ofcontrol elements associated with the structure; and

FIGS. 21 to 28 are wiring diagrams of the control circuit for the apparatus.

GENERAL ARRANGEMENT AND OPERATION The general arrangement of preferred apparatus for sorting and stacking veneer sheets, embodying the present invention, is best shown in FIGS. I and 2 of the drawings. The apparatus includes a sorter-stacker apparatus A that received veneer sheets of different widths from a veneer clipper (not shown) via a preliminary sorter B and a feed conveyor C. The preliminary sorter B is used to eliminate defective or scrap pieces of veneer. The sorterstacker apparatus A sorts and stacks sheets according to size and deposits the stacks on a takeoff conveyor D, from which the stacks are removed in any conventional manner.

Sheets of veneer are received by the sorter-stacker apparatus A from the conveyor C by an overhead conveyor E of the sorter-stacker apparatus A. The sheets are held in frictional engagement against the lower reaches of the overhead conveyor E by a pressure differential created by a vacuum generator assembly F, and are moved by the conveyor E to stacking stations at which the sheets are deposited according to size. In the embodiment shown, two such stacking stations H, H are employed, in the first of which wider sheets are stacked. The presence of a sheet of proper width is sensed photoelectrically when the sheet is over the stacking station in which it is to be stacked. More or less than two stacking stations can be provided as desired. It is also to be understood that different sensing equipment may be employed and that the sheets may be stacked according to grade or quality of veneer, thickness, etc., by the use of suitable sensing equipment.

Associated with each stacking station is a sheet stripper mechanism L, L and a sheet kicker mechanism M, M for removing veneer sheets from the overhead conveyor. The sheets are positioned in an orderly stack at each station by a side aligning mechanism that receives and aligns the leading sides or edges of the veneer sheets as they are removed from the overhead conveyor and an end aligning mechanism that aligns the ends of the sheets.

The stripping mechanism or stripper is above the overhead conveyor and is lowered to strip the leading edge of a veneer sheet from the overhead conveyor and to guide it to the edge aligning mechanism. The kicking mechanism or kicker kicks the trailing portion of the veneer sheet being stripped from the 

1. A method of stacking veneer sheets including the steps of transporting sheetS of veneer along a path above a plurality of stacking stations, frictionally engaging an upper surface of the veneer sheets with a moving member, maintaining the sheets in contact with said moving member by reducing ambient pressure above said sheets, diverting sheets from said path to said stacking stations, gripping a leading edge of each transported sheet at locations across the sheet only after it is at least partially diverted from said path and pulling the edge against an aligning abutment at the stacking station, and thereafter releasing said gripped edge and allowing the sheet to settle and form a stack of sheets in which leading sheet edges are aligned.
 2. A method of stacking veneer sheets including the steps of transporting veneer sheets of different character along a path, selectively diverting sheets from the path at different locations to form plural stacks each of sheets of a similar character, receiving and supporting a leading portion of diverted sheets at a location vertically displaced from said path on members movable in the general direction of sheet travel along said path, clamping a leading portion of a diverted sheet against said movable members and pulling each diverted sheet by the clamped leading portion in the direction of travel against a stationary abutment and continuing to move said movable members in the direction of travel to release said diverted sheet to a stack with the leading edge aligned therewith.
 3. A method of stacking veneer sheets including the steps of transporting veneer sheets of different character along a path, selectively diverting sheets from the path at different locations to form plural stacks each of sheets of a similar character, introducing a flow of air beneath each sheet as it is diverted to partially support or cushion the sheet, receiving and supporting a leading portion of diverted sheets on members displaced vertically from said path and movable in the general direction of sheet travel along said path, clamping said leading sheet portion against said movable members and pulling each diverted sheet by the clamped leading portion in the direction of travel against a stationary abutment while the flow of air is continued, and continuing to move said movable members in the direction of travel to release said diverted sheet to a stack with the leading edge aligned therewith.
 4. A method of sorting and stacking veneer sheets, including the steps of conveying sheets of different size along a path over stacking stations, detecting the size of the sheets and directing conveyed sheets of common size downward from said path to a common stacking station, engaging a leading portion of a downwardly directed sheet and aligning the leading edge against an abutment, supporting the aligned sheet on a stack of sheets, aligning side edges of the sheet to the stack, sensing the top of the stack when it reaches a predetermined level and lowering the stack a limited distance in response to said sensing to maintain the distance from the top of the stack to said path between predetermined upper and lower limits, and removing the stack from the stacking station after the stack reaches a predetermined size.
 5. Apparatus for stacking veneer sheets, including a support structure, a driven conveyor carried by said support structure and defining a horizontal path of movement for veneer sheets, means along said conveyor to reduce ambient pressure above at least portions of said path to cause the veneer sheets directly beneath said conveyor to be biased against the conveyor, an upright abutment beneath said path for obstructing movement and aligning leading edges of sheets diverted from the conveyor to form a stack, means upstream from said abutment relative to the direction of sheet travel to selectively engage a moving veneer sheet and divert it downward from the conveyor, and movable means adjacent said path of movement and adjacent said abutment to engage a leading portion of a diverted sheet in front of said abutment and to partially Support and carry the sheet against said abutment and to thereafter release said sheet.
 6. Apparatus for stacking veneer sheets, including a support structure, a driven conveyor carried by said support structure and defining a horizontal path of movement for veneer sheets, means along said conveyor to reduce ambient pressure above at least portions of said path to cause the veneer sheets directly beneath said conveyor to be biased against the conveyor, an upright abutment beneath said path for obstructing movement and aligning leading edges of sheets diverted from the conveyor to form a stack, means upstream from said abutment relative to the direction of sheet travel to engage and divert moving veneer sheets downward from the conveyor, movable sheet receiver means beneath said path and adjacent said abutment and including a lower extending support part reciprocable along the general path of sheet movement for initially receiving and supporting a leading portion of a diverted sheet and an upper sheet clamping part movable toward and away from said lower support part to clamp a sheet received on said lower support, means to move said upper sheet clamping part toward and away from said lower part, and means to reciprocate said sheet receiving means along the general path of sheet movement to carry a supported sheet into engagement with said abutment.
 7. Apparatus for stacking veneer sheets, including a support structure, a driven conveyor carried by said support structure and defining a horizontal path of movement for veneer sheets, means along said conveyor to reduce ambient pressure above at least portions of said path to cause the veneer sheets directly beneath said conveyor to be biased against the conveyor, an upright abutment beneath said path for obstructing movement and aligning leading edges of sheets diverted from the conveyor to form a stack, means upstream from said abutment relative to the direction of sheet travel to divert moving veneer sheets downward from the conveyor, an arm upstanding from a support beneath said path of movement, the upper end of said arm being located beneath said path and having a sheet gripper extending from the upper end in a direction generally along the said path opposite to the direction of sheet movement, said gripper including lower and upper members relatively movable between open or spaced relationship and closed or clamping relationship, means to pivot said arm between a forward position in front or upstream of said abutment, and means to close said upper and lower members adjacent the forward position and to open said members adjacent the withdrawn position whereby said pivoted arm can be reciprocated to receive and grasp a leading portion of a diverted sheet upstream of said abutment, guide and move said sheet to position a leading edge of the sheet against said abutment and to release said sheet in predetermined alignment with a stack.
 8. Apparatus for stacking veneer sheets, including a support structure, a driven conveyor carried by said support structure and defining a horizontal path of movement for veneer sheets, means along said conveyor to reduce ambient pressure above at least portions of said path to cause the veneer sheets directly beneath said conveyor to be biased against the conveyor, an upright abutment beneath said path for obstructing movement and aligning leading edges of sheets diverted from the conveyor to form a stack, means upstream from said abutment relative to the direction of sheet travel to divert moving veneer sheets downward from the conveyor, and at least two arms upstanding from a support beneath said path, adjacent said abutment and pivoted about an axis transverse to said path of movement, the upper end of each arm being located beneath said path and having means to grasp a leading portion of a diverted sheet and to partially support and move the sheet in a forward direction against said abutment, and means to alternately move said two arms forward and back about said pivot to engage aLternate ones of conveyed sheets.
 9. Apparatus for stacking veneer sheets, including a support structure, a driven conveyor carried by said support structure and defining a horizontal path of movement for veneer sheets, means along said conveyor to reduce ambient pressure above at least portions of said path to cause the veneer sheets directly beneath said conveyor to be biased against the conveyor, an upright abutment beneath said path for obstructing movement and aligning leading edges of sheets diverted from the conveyor to form a stack, means upstream from said abutment relative to the direction of sheet travel to divert moving veneer sheets downward from the conveyor, movable means adjacent said path of movement and adjacent said abutment to engage a leading portion of a diverted sheet and to partially support and carry the sheet in a forward direction against said abutment and to thereafter release said sheet, a sheet support beneath said conveyor for receiving diverted sheets with leading edges aligned, means to lower said sheet support to prevent a supported stack of sheets from extending above a predetermined level, sheet aligners movable transversely of said path to engage and align edges of stacked sheets that extend in the direction of sheet movement, and sheet sensing means carried by a sheet side aligner to actuate said means to lower said sheet support when said stack reaches said predetermined level.
 10. Apparatus for stacking veneer sheets, including a frame structure, a driven conveyor carried by said frame structure and defining a horizontal path of movement for veneer sheets, means along said conveyor to reduce ambient pressure above at least portions of said path to cause the veneer sheets directly beneath said conveyor to be biased against the conveyor, an upright abutment beneath said path for obstructing movement and aligning leading edges of sheets diverted from the conveyor to form a stack, means upstream from said abutment relative to the direction of sheet travel to divert moving veneer sheets downward from the conveyor, means for engaging a leading portion of a veneer sheet at locations across the sheet, said means including a movable sheet receiver beneath said path and adjacent said abutment and including a lower extending support part reciprocable along the general path of sheet movement for initially receiving and supporting a leading portion of a diverted sheet and an upper sheet clamping part movable toward and away from said lower support part to clamp a sheet received on said lower support, and means to move said upper sheet clamping part toward and away from said lower part and to reciprocate said parts along the general path of sheet movement, said upright abutment including a portion beside and directly adjacent said movable sheet receiver located to abut a leading edge of the sheet directly beside a portion of the sheet engaged by said sheet receiver to prevent distorting or tearing of the sheet when the sheet is moved by said sheet receiver into contact with said abutment.
 11. Apparatus for stacking veneer sheets, including a support structure, a driven conveyor carried by said support structure and defining a horizontal path of movement for veneer sheets, means along said conveyor to reduce ambient pressure above at least portions of said path to cause the veneer sheets directly beneath said conveyor to be biased against the conveyor, an upright abutment beneath said path for obstructing movement and aligning leading edges of sheets diverted from the conveyor to form a stack, means upstream from said abutment relative to the direction of sheet travel to divert moving veneer sheets downward from the conveyor, movable means beneath and adjacent said path of movement and adjacent said abutment to engage a leading portion of a diverted sheet and to partially support and carry the diverted sheet in a forward direction against said abutment and to thereafter release said sheet, and means beneath said conveyor to temporarily increAse the air pressure beneath a diverted sheet when a leading portion is engaged by said movable means to partially support the sheet during its downward movement from the conveyor to a positive support.
 12. In apparatus for aligning and stacking veneer sheets moved along a generally horizontal path, two sets of aligning arms each supported for pivotable movement about an axis perpendicular to the path of sheet movement and generally parallel to leading edges of said sheet, arms of each set being located beneath and spaced transversely of said path, means to alternately pivot the set of arms from a rearward or returned position to a forward position in a direction opposed to that of the sheet movement along the path and thereafter to a returned position, each arm including a movable jaw, and means to close the jaws when the respective arms are in a forward position, to hold the jaws closed while said arms are pivoted to a rearward position, to open the jaws when the arms are in said rearward position, and to carry the jaws forward in an open condition.
 13. Apparatus for sorting and stacking veneer sheets including support structure, a driven conveyor carried by said support structure and defining a horizontal path of movement for veneer sheets, means along said conveyor to reduce ambient pressure above at least a portion of said path to cause veneer sheets directly beneath said conveyor to be biased against the conveyor, at least two stacking stations spaced longitudinally beneath said conveyor for receiving veneer sheets of different characteristics, detecting means along said path sensitive to different characteristics of veneer sheets carried by said conveyor, means above each stacking station to divert sheets of selected predetermined characteristics downward from the conveyor in response to detection thereof by said detecting means, an abutment beneath said path at a forward portion of each stacking station relative to the direction of sheet movement for obstructing forward movement of the leading edge of sheets diverted from the conveyor, movable means at a forward portion of each stacking station adjacent said abutment to partially support and carry the sheet in a forward direction against said abutment and to release the sheet, vertically movable means at each stacking station beneath the conveyor to support aligned sheets, side aligning means on opposite sides of the path of sheet movement movable transversely of the direction of sheet travel to engage and align sheets on said support means, means to intermittently move said side aligning means toward each other to engage and align veneer sheets on said support, means for sensing a predetermined height of a stack of veneer sheets on said support means, and means to move said support means vertically downward a predetermined distance in response to the sensing of the veneer stack by said stack height sensing means.
 14. Apparatus for sorting and stacking veneer sheets including support structure, a driven conveyor carried by said support structure and defining a horizontal path of movement for veneer sheets, means along said conveyor to reduce ambient pressure above at least a portion of said path to cause veneer sheets directly beneath said conveyor to be biased against the conveyor, at least two sheet stacking stations spaced longitudinally beneath said conveyor for receiving veneer sheets of different width, sheet detecting means along said path sensitive to different predetermined widths of veneer sheets to detect the presence and size of veneer sheets carried by said conveyor, means above each stacking station to divert sheets of predetermined width downward from the conveyor in response to detection thereof by said sheet detecting means, arm means adjacent the front of each stacking station beneath said conveyor to receive and align sheets of veneer diverted from said conveyor, said arm means being selectively pivotable from rearward to forward positions initiated in response to the sensing by said sheet detectIng means of a veneer sheet of a size to be diverted to the respective stacking area, and said arm means having a movable jaw initially open when said arm means is in a forward position, said jaw being movable to a closed condition after a time delay in response to the sensing by said sheet detecting means of a veneer sheet of a size to be diverted to the respective stacking station, to yieldably engage a leading edge of a diverted veneer sheet and to thereafter move the arm to a rearward position, an abutment to obstruct movement of a veneer sheet carried by said arm means to cause said sheet to slide from said jaw when against said abutment, means to open said jaw when said arm is in a rearward position, means to supply air under pressure to a zone beneath a diverted sheet to partially support the sheet during engagement and movement of the sheet by said arm means, and vertically movable means at each stacking station beneath the conveyor to support aligned sheets, side aligning means on opposite sides of the path of sheet movement movable transversely of the direction of sheet travel to engage and align sheets on said support means, means to intermittently move said side aligning means toward each other to engage and align veneer sheets on said support, means for sensing a predetermined height of a stack of veneer sheets on said support means, and means to move said support means vertically downward a predetermined distance in response to the sensing of the veneer stack by said stack height sensing means.
 15. In apparatus for stacking veneer sheets beneath an overhead conveyor, a support on which veneer sheets are stacked, means to move the support vertically downward in increments to maintain the top of a supported stack between predetermined upper and lower levels as sheets are added to the stack, means movable toward and away from the stack adjacent the predetermined upper level to align a supported sheet, and means carried by said movable means for sensing the presence of the stack on the support at said predetermined upper level to initiate downward movement of said support.
 16. Apparatus for sorting and stacking veneer sheets, including support structure, a driven conveyor carried by said support structure and defining a horizontal path of movement for veneer sheets, means along said conveyor to reduce ambient pressure above at least a portion of said path to cause veneer sheets directly beneath said conveyor to be biased against the conveyor, at least two stacking stations spaced longitudinally beneath said conveyor for receiving veneer sheets of different sizes, sensing means located along said path for distinguishing between veneer sheets of different sizes carried by said conveyor, means adjacent each stacking station for selectively diverting sheets downward from said path, and movable means beneath said path and adjacent each stacking station for at least partially receiving, supporting and carrying a diverted sheet into an aligned position relative to a stack of sheets at the respective station, and means for actuating said means for diverting sheets at a particular stacking station in response to the detecting of a sheet of a size to be stacked therein by said sensing means.
 17. Apparatus for sorting and stacking veneer sheets, including support structure, a driven conveyor carried by said support structure and defining a horizontal path of movement for veneer sheets, means along said conveyor to reduce ambient pressure above at least a portion of said path to cause veneer sheets directly beneath said conveyor to be biased against the conveyor, at least two stacking stations spaced longitudinally beneath said conveyor for receiving veneer sheets of different sizes, sensing means located along said path for distinguishing between veneer sheets of different sizes carried by said conveyor, means adjacent each stacking station for selectively engaging and diverting sheets downward from said path, and movable means beneath said path and adjacent each staCking station for at least partially receiving, supporting and carrying a diverted sheet into an aligned position relative to a stack of sheets at the respective station, said movable means including a portion engageable by said means for diverting sheets and movable thereby from a sheet receiving position to a position in which the sheet is aligned with other sheets at the station and released, and means for actuating said means for diverting sheets at a particular stacking station in response to the detecting of a sheet of a size to be stacked therein by said sensing means. 